[
https://issues.apache.org/jira/browse/MRUNIT-127?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13426560#comment-13426560
]
Dave Beech commented on MRUNIT-127:
-----------------------------------
If the custom sorting comparator orders things such that all the keys which
should be grouped together fall next to each other, then yeah, you're fine.
Otherwise MapReduce and MRUnit will give you different answers.
> Key grouping with GroupingComparators is not consistent with MapReduce
> behaviour
> --------------------------------------------------------------------------------
>
> Key: MRUNIT-127
> URL: https://issues.apache.org/jira/browse/MRUNIT-127
> Project: MRUnit
> Issue Type: Bug
> Affects Versions: 0.9.0
> Reporter: Dave Beech
>
> In Hadoop MapReduce, for a set of keys to be properly grouped together by a
> grouping comparator into a reduce call, they need to be in a contiguous range
> when sorted by the key's ordering comparator.
> MRUnit does not impose this requirement, so if the user's grouping and
> sorting comparator logic is incorrect, their tests may pass and give the
> expected result even though the outcome would be different when run as a true
> MapReduce job.
> (see below for further explanation)
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators:
https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira
